Artificial limb



Aug. 20, 1929. J, H. KosEK ARTIFICIAL LIMB Filed Sept. 10, 1925 PatentedAug. 29, 1929.

UNITED STATES 1,725,588 PATENT OFFICE.

JOSEPH H KOSEK, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR TO DAVID W. DOB

RANGE, OF MINNEAPOLIS, MINNESOTA.

ARTIFICIAL LIMB.

Application filed. September 10, 1925.

My invention relates to improvements in artificial limbs andparticularly to a hand appliance adapted to be attached to an armstumpsocket and operated through the usual pullcord anchored to one of theshoulders of a wearer.

An object of the invention is to provide a simple, durable andrelatively inexpensive substitute for the human hand, the same includinga pair of complementary fingers and means for opening and yieldinglyclosing said fingers, said means embodying a toggle mechanism throughwhich a pullcord easily acts to open said fingers, but by virtue ofwhich said fingers otherwise are powerfully held against opening.

Another object is to supply an article of the present nature in whichfinger tip members on oppositely bowed fingers form convenient hooks.

With the foregoing and other objects 1n view, which will appear in thefollowing description, the invention resides in the novel combinationand arrangement of parts and in the details of construction hereinafterdescribed and claimed.

In the drawings, Fig. 1 is a perspective view of an article embodyingmy, invention, the same being illustrated as applied to an arm-stumpsocket, Fig. 2 is a plan View of said article, a portion of the shankhead being broken away to show clearly those portions of the fingers andtoggle mechanism that are otherwise concealed, and Fig. 3 is a detailview partly in plan and partly in sec tion, the same illustratingparticularly the butt end of the shank and the plunger of the togglemechanism.

Referring to the drawings, it will be seen that my improvement includesa shank A and fingers 10. The shank A is threaded exteriorally at thebutt thereof, the tip being bifurcated to form a yoke-like head havingopposed, spaced head members or plates a. The shank A, formed with anaxial bore 11 therein opening between the head plates at, provides asocket for a plunger spring 12 and plunger 13 to be more fullyhereinafter described. The fingers 10 are oppositely bowed and arepivoted at their butts to and between the ends of the head plates a bymeans of pintles 14, said fingers being formed with inter-meshing gearsegments 15 formed thereon and struck from centers in' the axes of theirrespective pintles 14:. Ex-

Serial No. 55,485.

tending rearwardly and outwardly from the butt of each finger 10 is anarm 10 The previously mentioned plunger spring 12 is a helical expansionspring which is seated at one end thereof in the bore 11 in the shank A.One end of the plunger 13 is fitted within this spring, said plungerhaving an arm 13 thereon, the same abutting against the free end of thespring and extending outwardly from and between the head plates w. Thehead of the plunger 13 is kerfed as at 13 the ends of the arms 10 of thefingers 10 being also kerfed as at 10 and in the same plane as the kerfin the plunger 13. A pair of toggle links 16 are disposed at their innerends in the kerf 13 of the plunger 13 and pivoted to said plunger bymeans of pintles 17. The outer end of one toggle link 16 is fitted inthe kerf 10 of one arm 10? and pivoted to said arm by a pintle 18, theouter end of the other toggle link 16' being likewise fitted in the kerf10 in the other arm 10 and pivoted to said arm.

The free end of each finger 10 merges into a flattened tip member 10which extends bearing against a resilient washer 21 re-,

cessecl in said head of said socket. With the article thus attached tothe socket 19, the pull cord 22 is connected with the actuating arm 13on the plunger 13. In retracted position of the stump socket, whereinthe cord 22 is loose, the spring 12 operates through the plunger 13 andtoggle links 16 to yieldingly close the fingers 10 and clamp the tipmembers 10 together face-to-face (solid lines, Fig. 2). Under a forwardthrust of the arm socket 19 and due to the pulling of the cord 22 on thearm 13 as a result of such thrust, the plunger 13 is retracted againstthe action of the spring 12. Thus retracted, the plunger 13 separatesthe fingers 10 through the medium of the toggle links 16, the movementsof said fingers 10 being co-ordinated by reason of the intermeshing gearsegments 15. With the tip members 10 of the fingers engaged one with theother (solid lines, Fig. 1), the toggle links 16 are almost on center,the result being that forces required in opening the fingers 10 byapplication to said fingers themselves must be much greater than thestrength of the spring 12. And the same holds true in the variousseparated positions of the fingers 10. In taking the bail of a bucket orin catching any such small object through which weights or pulls are tobe met in the artificial hand, it is convenient to catch the same in oneof the hooks formed by one of the fingers 10 and its respective tipmember 10. With an object caught in one of these hooks, none oftheiesistance occasioned thereby has any tendency to spread the fingers10, My device, therefore, is adaptedto uses that could not be served inthe absence of a spring 12 so powerful as to negative ease of operationin carrying out other important uses.

Changes in the specific form of my invention, as herein disclosed, maybe made with in the scope of what is claimed without departing from thespirit of my invention.

Having described my invention, what I claim as new and desire to protectby Letters Patentisz' 1. In an article of the class described, a shankfor attachment to an arm-stump socket, said shank having a bifurcatedhead and an axial bore opening into the space between the spaced headmembers, co-operating fingers fitted at the butts thereof between saidhead members and pivoted thereto, said fingers being geared together andeach thereof formed with a rearwardly projecting arm, a coiled expansionspring seated within said bore in said shank, a plunger fitted withinsaid spring, said plunger having an arm near the head thereot, said armextending out- Ward between said head members and abutting against thehead of said spring, and a pair 0t links, one for each finger, each linkbeing pivoted at one end thereof to the arm of its respective finger andat its other end to the head of said plunger.

2. In an article of the class described, a shank for attachment to anarm-stump socket, co-operating fingers pivoted on said shank and geared,one to the other, a spring pressed plunger mounted on the shank, togglelinks connecting said plunger with said fingers, and an arm on saidplunger for retracting the same to open said fingers.

3. In an article of the class described, a shank for attachment to anarm-stump socket, a pair oi oppositely bowed complementary pivotedfingers carried on said shank, means to bring said fingers together atthe tips thereof, each finger having a flattoned tip member, a portionof each member extending back into the space between said bowed fingersto form an inside hook, the remaining portion of each member extendingtoone side and co-operating one with the other to grip articles at theside of said fingers. V

4. In an article of the class described, a member for attachment to anarm stump socket, a second member movable relative to said first namedmember, a pair of complemental fingers pivoted to one of said members,and a pair 01": links each pivoted at on end to one of said fingers andat its other end to said other member, the pivots or said links beingadapted to lie in substantial alignment in the closed position of saidfingers.

, In testimony whereof, I have signed my name to this specification.

JOSEPH H. KOSEK.

